Electric release mechanism for knitting machines



May 13, 1941. D. WACHSMAN ELECTRIC RELEASE MECHANISM FOR KNITTING MACHINES Filed April 6, 1940 INVENTOR.

Patented May 13, 1941 ELECTRIG RELEASE MECHANISM FOR KNITTING MACHINES David Wachsman,

Brooklyn, N. Y., assignor to Wachsman Sons, Inc., a. corporation of New York Application April 6, 1940, Serial No. 3:28.251

1 Claim.

This invention relates to electric release mechanisms for knitting machines of the type disclosed in the U. S. Patent 1,845,455, February 16, 1932. The object of the invention is to provide an improved type of such release mechanism for actuating the stop handle of the driving unit of the machine when a thread breaks or runs out. One object is to provide a device in which the number of parts are reduced to a minimum together with certain novel features of design and construction providing a mechanism easy and inexpensive to 'manufacture, easy to assemble and install and having certain features of construction facilitating easy adaptation to knitting machines stop mechanisms. In the accompanying drawing illustrating the invention- Fig. 1 is a view in elevation of the release mechanism which is contained in a box the cover of which is removed.

Fig. 2 is a longitudinal sectional view through the box on the line 22 of Fig. 1 with some details left out.

Fig. 3 is a transverse sectional view on the line 33 of Fig. 2 with parts omitted.

Fig. 4 is a diagram.

Referring first to Fig. 4 the numeral l indicates conventionally a stop handle of a driving unit in a knitting machine. When the handle is swung on its pivot II the knitting machine stops. The operation is similar to that of shifting a belt pulley in other machinery. In knitting machines the operation of the stop handle is controlled by the thread. That is, when the thread breaks or runs out the handle H] is to be operated to stop the machine. The controlling mechanism is in the form of a switch which is normally held in circuit open position by the thread. Such switches are called end detectors or knot detectors or stop motions in the art. In Fig. 4 it will be seen that the thread l2 runs over two guides I3, l3 and that a detector l4 rests upon the thread. The detector M is merely a switch arm which, when not supported by the thread, moves down by any suitable means and contacts a switch plate which is grounded. The detector is connected to a battery It. This in turn is connected to an electromagnet II. The other end of the coil is connected to a spring contact l8 which is grounded. It will therefore be seen that so long as the switch or detector I4 is supported by the thread the circuit is open and the electromagnet cannot attract its armature lever I9.

The latter acts to hold a locking lever 20 in position to lock a plunger 2! against movement by the action of a plunger spring 22. The plunger is adapted to move the stop handle IE! as shown. If new the detector switch is closed because the thread breaks or runs out, the circuit is closed, the magnet is energized, the armature lever I9 is actuated to release the locking lever 20 which falls down by gravity thereby releasing the plunger 2|. The latter is then moved by the plunger spring 22 to throw the stop handle [0 to stop the machine and the circuit is then immediately open at the spring contact l8. Thus only for a moment is. the circuit closed. This is the usual procedure to avoid accidents due to shocks. The detector switch and other parts in Fig. 4 are shown wholly conventional. The foregoing is a brief description of'the operation of a typical electric stop mechanism for knitting machines. This invention' is concerned with the construction and arrangement of those parts of the mechanism whereby the plunger is held, operated and again set for the next operation.

Referring now to Figs. 1 to 3 the plunger 2! is slidably supported in two cut cuts or slots 24, 24 in the box 25 which contains and supports the several parts. The box has a cover 26 with overhanging lips 21, 21 extending down over the said slots to keep the plunger therein so it cannot jump out or tip. 28 which engages a nose 29 on the locking lever 20. The latter is relatively very long and pivoted at 30. The long arm 3| of the lever 20 tends to fall down to the bottom of the box 25 by gravity but is normally prevented therefrom by the armature lever 19 which has a lip 32 which engages under a hook 33 on the locking lever.

The armature lever is pivoted at 34 in the box and is urged away from the magnet l1, H by a spring 35. A stop 36 positions the armature lever with relation to the magnet. Current is supplied to the latter by way of a :circuit terminal 31 which is also connected to the aforesaid spring contact l8. In normal position when the magnet is not energized the locking lever 20 engages the spring contact I8. The lever is preferably of brass or other conducting material so the circuit at I8 is grounded on the box via the lever 20. A pin 40 is provided for manual operation of the armature lever I!) to test the device by pushing the pin inward whereby to release the locking lever.

In operation the normal positions of the parts are as shown in the drawing. The operator has pushed the plunger 2| to the left in Figure 1 to compress the spring 22. In moving the plunger against the spring the plunger hook 28 hits an- The plunger carries a hook other nose 42 on the locking lever 20 thereby tipping the latter anticlockwise on the pivot 30. Thus the long arm 3| is raised and the hook 33 snaps up past the armature lever hook 32 and comes to rest thereupon by gravity, the plunger at the same time being pushed slightly to the right in Fig. l but being locked against movement in either direction by the locking lever nose 29. When now the magnet is energized due to the closing of the circuit at I i-I5, Fig. 4, the armature lever hook 32 moves away from the locking lever hook 33, the locking lever falls down and the plunger is released. The spring then pushes the plunger to the right in Fig. 1 to operate the stop handle. The spring 22 is very strong so the plunger moves very quickly and the hook 28 would strike the wall of the box with a blow. However a cushion spring 44 takes the blow by the hook 28. When the locking lever drops the circuit is broken at E8, the magnet is deenergized, and the spring 35 moves the armature lever into position as shown ready to catch the hook 33 of the locking lever when the release is reset by the operator.

This releasing device is: extremely simple to construct and assemble. After the armature lever and magnet are mounted, the locking lever is easily inserted to catch the contact I8, the pivot 30 being put in from the outside. Then the plunger is dropped into the slot 24, the cover put on and the device is then ready for installation and operation. I-Ieretofore, so far as I know, such releases have had a plurality of levers for various purposes interposed between the armature lever and the plunger. This device uses only one lever 20. The release is readily prepared for driving units having different throws of the stop handle by merely lifting out the plunger, removing a pin 50, Fig. 3 to detach the hook 28 by a sliding movement and putting another hook on having a length whereby the movement of the plunger to the right in Fig. 1 will be of a length to correspond with the movement of the stop handle. The longer the hook 28 the sooner it hits the cushioning spring 44 and the shorter is the plunger movement and vice versa.

I claim:

In an electric release for knitting machines wherein is provided an electric circuit with a normally open circuit closer controlled by a travelling thread and which includes a stop handle; a plunger for actuating said stop handle, a hook on said plunger, a spring for moving the plunger in one direction, a gravity actuated plunger locking lever, two noses thereon, one of said noses engaging said plunger hook to hold the plunger immovable against the action of said spring, an electromagnet in said circuit, an armature lever for said magnet, interengaging cooperating means on said locking lever and on said armature lever for holding said looking lever nose in engagement with said plunger, the second nose on said locking lever engageable by said plunger hook to move the locking lever from a gravity actuated position into plunger holding position by said first named nose, said interengaging means on the locking and armature levers being disengaged when the armature lever is attracted by the magnet whereby to cause the locking lever to become gravity operated to release the said plunger for action by said spring.

DAVID WACI-ISMAN. 

